The disclosure relates to a hydraulic toothed wheel machine.
EP 1 291 526 A2 shows a toothed wheel machine having a housing in which two intermeshing toothed wheels supported in bearing bushes or bearing bodies are arranged, the housing being closed at the ends by a first and a second housing cover respectively. The helically toothed wheels are each supported in a sliding manner axially by two axial surfaces between the bearing bodies and radially by respective bearing shafts accommodated in the bearing bodies. During the operation of the toothed wheel machine, hydraulic and mechanical forces act on the toothed wheels along the same toothed wheel longitudinal axis in each case. To ensure that the first bearing body, which lies in the direction of action of the forces, is not pushed beyond the axial surfaces of the toothed wheels, between the toothed wheels and the first housing cover, and that only a small sliding gap occurs between the toothed wheels and the second bearing body, a counter-force is applied to the toothed wheels and to the first bearing body. This counter-force is larger than the hydraulic and mechanical forces, with the result that the first bearing body is pressed against the toothed wheels, the toothed wheels are pressed against the second bearing body, and the second bearing body is pressed against the second housing cover. All the resultant forces on the bearing bodies and the toothed wheels thus act in the direction of the second housing cover.
The counter-force on the toothed wheels is applied via pistons acting on the bearing shafts. The pistons are accommodated in a sliding manner, approximately coaxially with respect to the toothed wheel longitudinal axis, in an intermediate cover arranged between the first housing cover and the housing and rest by means of a first piston end face against a shaft end face of the bearing shafts which faces in the direction of the first housing cover and are each subjected to pressure by way of a second piston end face. The counter-force is applied to the first bearing body by way of a pressure field formed between the bearing body and the intermediate cover.
The disadvantage with this solution is that the entire assembly of bearing bodies and toothed wheels is pressed onto the second housing cover of the toothed wheel machine, with the result that the second housing cover and the housing are subjected to very high and uneven loads. Moreover, the pressing together of the toothed wheels and the bearing bodies results in very high wear between the axial surfaces of the toothed wheels and the bearing bodies.